Allow configuring language for auto-generated session titles in Recents

Problem

In the Claude desktop app (claude.ai/code), the "Recents" sidebar shows auto-generated session titles. For non-English users, these titles are almost always generated in English, even when:

• The entire conversation is in the user's native language (e.g., Chinese)
• The user's global ~/.claude/CLAUDE.md explicitly requests responses in their native language
• The first user message is in their native language

Example from my account (all conversations were conducted in Chinese):

• "Investigate web3 research MCP project"
• "Compare image quality of popular AI..."
• "Research and analyze two GitHub projects"
• "Set up Superpowers repository"
• "List Changsha attractions by category"

This forces non-English users to mentally translate every title when scanning Recents — a meaningful daily friction.

Why current workarounds don't work

• CLAUDE.md is not read by the title-generation service
• settings.json has no summaryLanguage / titleLanguage field
• No hook can intercept title generation
• Manually renaming each conversation is tedious

Proposed solutions (any one would help)

1. Account-level setting: a "Session title language" dropdown in Settings (Auto / English / 中文 / 日本語 / …)
2. Follow conversation language: have the title-generation model match the language of the first user message (lowest-effort fix — would silently solve it for everyone)
3. Respect language field in ~/.claude/settings.json if present
4. Read user CLAUDE.md when generating titles

Impact

This affects every non-English Claude Code user. Option 2 is probably the smallest change and would default-fix it for the whole non-English userbase.